Wow I just googled this so I hope this is a good site. I have a tankless water heater in my basement and love it! Problem is I need to waste so much water for my second floor bath to get water to my sinks. I was told I can install a plug in small tankless water heater under one of my sinks (they are side by side) and cap off my hot water (which has a 1/4 turn shut off on it) and hook up the tankless hot water supply to both sinks? Am I explaining this right?

Welcome to The Plumbing Page at AMHD.com.
You have explained it just fine. The supply each lavatory you have to shut the water off at the house. Shut off and cap off the hot water supply to one of the lavatory's.
On the other lavatory. You will connect the inlet of the tankless to the hot water supply coming out of a wall and connect the tankless outlet to both of the supplies to the hot water side of your faucets. Is this what you want to know? Good luck, Tom

Hello Tom and thanks for the fast reply :o) I hope it is OK that I ask this follow up question below just so I'm clear and thanks for your help!

You have explained it just fine. Thank you. The supply each lavatory you have to shut the water off at the house. Can I use just the shut offs under the sink?

Shut off and cap off the hot water supply to one of the lavatory's. Ok I got this part and it has a 1/4 turn shut off on it. Can I just turn this off or add a shark bite?

On the other lavatory. You will connect the inlet of the tankless to the hot water supply coming out of a wall and connect the tankless outlet to both of the supplies to the hot water side of your faucets. Is this what you want to know? Ok so I attached a like below. When you say inlet is that the water supply to the unit? So will this require a "T" copper or shark bite fitting to connect to both hot water sections. Also am I basically 1. Cutting off the hot water from coming up from the basement to one sink. 2. Taking the other hot water line and connecting it to the inlet of the unit. 3. Taking the "output" of the tankless water heater and attaching it to both of my hot water connections on my faucet? If so I need to some how "T" that hot water coming from the unit to both of my handles right?

Thank you again and sorry I tried using colors so I can separate your answer from my rambling question.
http://upload.wikimedia.org/wikipedia/commons/thumb/8/82/Kleindle.jpg/220px-Kleindle.jpg

Hi guys! Tom's explanation is off a bit up there (Tom has a program that types for him and it mistyped a couple things)...

As far as I can tell, it should be as simple as:

1) Shutting off the hot water supply valves to each sink... cap the 3/8" male compression valve threads on each valve with a 3/8" female threaded compression cap just to be extra safe.

2) Take one of the cold water supplies and connect it into the tankless heater cold supply pipe. Here, you can purchase a 3/8" compression tee fitting and fit that into the cold water line supplying one of the sink faucets...off this tee fitting you will run a properly sized/threaded braided supply hose into the cold water supply threads on the tankless heater.

3) Connect the hot water supply from the water heater to the hot water supply hose of the existing faucets (again, can use a 3/8" compression tee fitting to branch off and pick up both hot water supply hoses of the faucets).

Easiest installation will be to do all the connections/piping with properly sized/threaded SS braided hoses (like in the picture you posted)

That's it... ;)

Mark